Canon Extender EF 1.4x III (Tele Extender). Extending a lenses focal length by a factor of 1.4x, Extender EF 1.4X III incorporates phenomenal optical performance with minimal chromatic aberration and is a perfect complement to many of Canon super telephoto lenses. It features a built-in microcomputer for seamless communication among camera body, lens and extender; features careful lens placement and coatings to minimize ghosting and flare and even has a new Fluorine coating that keeps soiling, smears and fingerprints to a minimum. An integral part of many professional systems, Extender EF 1.4X III maintains high standards not only optically, but also in terms of rugged, dustproof and water resistant construction. IncludesLens Caps, LP811 Lens Pouch and Canon 1 Year Warranty-Product. Vendor Part # 4409B002

EF 70-200mm f/2.8L IS USM - AF Possible - If the lens is attached to an EOS camera, having multiple focusing points and an Extender is attached to the lens, only the center focusing point will be useable for AF.